Valves; Valve Stem Sealing Rings - Reassembly; Valve Springs; Valve Material - Kohler KD 625/2 Workshop Manual

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Disassembly / Reassembly
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Valves

Components:
1 Intake valve
2 Spring seat
3 Valve stem seal ring
4 Spring
5 Retainer
6 Half collets
To remove half collets firmly press down as shown in the figure.

Valve stem sealing rings - Reassembly

Lubricate the inside of the sealing ring with Molikote BR2 Plus and
insert them all the way onto the guides using tool 1460-108.
To prevent deformation of the sealing ring 1 as it is inserted onto the
valve guide 2 insert it onto tool 3.
Lubricate valve stem with the same type of grease; insert the valves
into the guides rotating them particularly as they enter the sealing
ring.

Valve springs

Measure free length with a gauge.
Using a dynamometer check that the spring length under two dìfferent
loads corresponds to the values below:
Free length A = 52 mm
Length B compressed by a 210.6 N = 35.8 mm
Length C compressed by a 340.6 N = 25.8 mm
Replace spring if length is 1 mm or more below the stated values.

Valve material

Intake valves A
Material: X 45 Cr Si 9-3 UNI En 10090
1 Chromium-plated portion
α 45.5° ÷ 45.75°
Exhaust valve B
Shaft and head are made of 2 different materials.
2 Welded portion
3 Chromium-plated portion
4 Portion made of X 45 Cr Si 9 - 3 UNI EN 10090
5 Portion made of X 55 Cr Mn Ni N 20 - 8 UNI EN 10090
α 45.5° ÷ 45.75°
KD 625-2 Workshop Manual_cod. ED0053029380_1° ed_ rev. 00